Disconnecting switch blade latch and pry out mechanism



April 2, 1957 A. N. FALLQWS 2,787,690

DISCONNECTING SWITCH BLADE LATCH AND PRY OUT MECHANISM Filed Sept. 8, 1953 2 Sheets-Sheet l INVENTOR. aaezr /V. @nou/5 April 2, 1957 A. N. FALLows 2,787,690

DISCONNECTING SWITCH BLADE LATCH AND PRY OUT MECHANISM Filed Sept. 8, 1953 2 Sheets-Sheet 2 United States Patent() DISCONNECTING SWITCH BLADE LATCH AND PRY OUT MECHANISM Albert N. Fallows, Greensburg, Pa., assigner to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Application September 8, 1953, Serial No. 378,708

Claims. (Cl. 200-169) My invention relates to a blade latch and pry out mechanism for a disconnect switch and is more particularly directed to a latch which is mounted on the surface of the jaw closest to the hinged end and a pry out means in which mechanical advantage is maintained during the initial separation of the blade from the jaw.

My novel mechanism is particularly adaptable to hook stick operated electrical disconnect switches of the knife blade variety. ln switches of this type, blades which are rectangular in cross section have one end pivotally mounted at a hinged terminal so that they may be manually rotated into and out of engagement with the jaw of the switch. The operation of the opening or the closing of the switch is a manual operation performed by v an operator with the aid of a hook stick which engages a pull ring attached to the jaw end of the blades.

ln switches of this type, it is desirable to have a positive latch to locate the switch blade in closed position to insure that they will not be opened due to electromagnetic forces set up by short circuit or fault current conditions or due to any other unintentional causes.

Although it is necessary to have the switch blade latched in the closed position, it is desirable to have the latch of such design that will permit opening operation with a single movement. That is, the construction of the latch and pry out mechanism should enable the operator to disengage the latch and the cooperating contacts with a single continuous force on the pull ring.

It is further desirable to obtain this maximum advantage and reliability of operation with a minimum cost.

Furthermore, since the contacts are maintained in high frictional contact engagement, it is desirable to incorporate somemeans to easily initiate the opening opera tion of the switch blades, that is, a pry out action which will be maintained over the initial increment of blade travel which is suicient to break any corrosive seal or ice formation to start the blades toward the open position. The novel latch pry ont arrangement of my invention is comprised of a resilient latch and a pull ring. Thereslient latch is mounted on a surface of the jaw of aswitch which faces the hinged end and engages a latch pin which extends .between the blades. The pull ring is pivotally mounted between the switch blades and has an extending portion which serves a dual function of releasing the latch engagement and provides pry out operation during initial opening operation.

My novel mechanism overcomes many of the disad# vantage's of the prior art arrangements and has many advantages thereover. For example, the simplicity of my device. ,The latch can be mounted directly onthe surface of the jaw facing the hinge end and hence does not require an extension of the switch blade past the jaw end.

Furthermore, the latch of my invention is a resilient member, thereby eliminating the necessity of providing auxiliary spring mounting means to the latch.V

A still further advantage of my device over that of the prior art is achieved by having an extension of a pull ring which performs the dual function of unlatching and providing pry out action by acting directly on the jaw of the switch without placing the strain on the latch or requiring intermediate force transmitting means.

Accordingly, a primary object of my invention is to provide a latch pry out mechanism which is relatively simple in construction, has a small number of component parts and can be manufactured and assembled at relatively low cost.

Another object of my invention is to provide a novel latch pry out mechanism which can be adapted to standard switches without extending the length of the blade.

A still further object of my invention is to provide a latch pry out unit to be used in connection with a hook stick operated disconnect switch having a blade member which need not be any longer than the center line distance between the hinge and the break tongue, plus half the width of the hinge tongue, plus half .the width of the break tongue.

A still further object of my invention is to provide an adapting unit for a disconnect switch which will perform both latching and pry out features thereto without requiring the extension of the blade member beyond the break tongue of the switch.

These and other objects of my invention will be apparent from the following description when taken in connection with the drawings in which:

Figure l is a side view of a disconnect switch and il lustrates the manner in which my novel latch and pry out mechanism can be adapted thereto. This figure illustrates the position of the various components when the switch is in the fully closed position.

Figure 2 is a top view of Figure l.

Figure 3 is a side view of the disconnect switch of Figures l and 2 and illustrates the position of the various parts when the switch is in the open position.

' The disconnect switch is mounted on insulators l0 and 1i which are in turn secured to the base l2 in any desirable manner.

The hinge end has a hinge member 14 secured by means of the bolts 17. The hinge member i4 has a protruding extending portion 16 which forms one terminal of the switch. Hinge member 14 also has an upwardly extending portion 19 on which the switch blades .3G-31 are pivotally mounted by means of the nut and bolt 32.

The jaw 15 is permanently secured to the insulator 11 by means of the bolts 18 and has an extending portion i6 which forms the second terminal of the disconnect switch. The jaw 15 has an upwardly extending portion et) which forms the break tongue or main jaw of the disconnect switch.

As best seen in Figure 2, the blades 30-31 straddle the breaktongue or jaw 49. A nut and bolt 98 are passed through the jaw end of the blades 30--31 and serve the following two functions.

a..As a pivot for. the pull ring 80.

b. To apply pressure to the contact pressure springs 110.

The jaw 40 is provided with elongated protruding portions 121 which serve to make electrical yengagement with the switch blades 30-31 when the switch is in the closed position. The switch blades 311-31 are provided with a latch pin 122 which extends therebetween and is secured thereto. The latch which engages the latch pin 122 when the switch is in the closed position is designated by the numeral 123. The latch 123 is preferably formed from a strip of non-corrosive non-magnetic spring material and is constructed in the shape of a hook 124 having a cam surface 125. The latch 123 is permanently secured to the jaw by means of two screws 141. It will be noted that the latch is secured to the surface of the jaw which faces the hinge end 14.

Thus, the hooked portion 124 of the resilient latch 123 engages the latch pin 122 when the switch is in the closed or engaged position to thereby maintain the contacts in engagement against an undue electromagnetic force or due to some unintentional jar or opening force. The ,pull ring 80 is provided with an eyelet 127 which is adapted to receive the end of a hook stick for the purpose of moving the switch blade to the open or closed position by an operator standing at a remote position from the switch.

The pull ring 80 is provided with a downwardly extending portion 123 which receives the bolt 98 to provide the pivotal mounting therefor and also has a lever 129 which serves to disengage the latch engagement 124-122 and also serves to provide pry-out action for the disconnect switch. The pull ring 80 is also provided with protruding portions 130 which extends over the upper surface of the switch blades 30--31, to thereby limit the counterclockwise rotation thereof.

The operation of the disconnect switch and the latch and pry-out mechanism is as follows:

When the switch is moved from the open position of Figure 3 to the closed position of Figures l and 2, the latch pin 122 will engage the cam surface 125 of the latch 123. Since the latch 123 is a resilient member, the closing force of the switch blades 30--31 will cause elastic deflection thereof to thereby remove the latch from the path of movement of the latch pin 122. As the blades 30--31 are moved into the closed position, the hook 124 of the resilient latch 123 will snap over the latch pin 122 and thus, lock the blades in the closed position.

When the operator desires to open the switch, a hook stick is inserted in the eyelet 127 of the pull ring S9 and the force exerted by the operator rotates the pull ring 80 in a clockwise direction indicated by the arrow 140 around the pivot point 98.

It will be noted that the pivot 98 of the pull ring 80 is also the center line of the contact pressure springs 110. Rotation of the pull ring 80 brings the lever 129 into contact with the cam surface 12S of the latch 123 and slides along this cam surface to thereby deflect the latch 123 about its stationary connecting point 141 to a position which permits the latch pin 122 to freely pass the latch 123 and thus allow the switch blades 30-31 to be rotated in a clockwise direction about the pivots 32 `to the open position.

At the point of travel, when the lever 129 of the pull ring 80 removes the latch 123 from the latch pin 122, it will come into contact with the top surface 143 of the jaw tongue 40. The lever 129 will position against the surface 143 of the break tongue 40 with a force which (neglecting friction) is equal to the moment about the pivot line 98 of the pull ring 80 of the force applied by the operator to the pull ring divided bythe straight line distance from the pivot line 98 to the point of contact between the pull ring lever 129 and the surface 143 of the jaw break 40.

Thus, the initial force tending to move the blades 30-31 out of the closed or engaged position of Figure l is equal to the force applied-to the jaw break 40 lby the pull ring lever 143. This pry-out action is maintained over an initial increment ofthe blade travel sufiicient to assure the breaking of any corrosive seal or ice formation and starts the blades 30-31 to move toward the open position. That is, during the opening operation of the switch blades 30-31, the pry-out action is effective from the time pull ring lever 129 touches the jaw tongue 143 until the pull ring lever 129 touches the latch pin 122.

The mechanical advantage realized by using this novel pry-out mechanism is sucient to substantially reduce the operating effort required to open the switch.

It will also be noted that a single continuous force applied by the operator serves to disengage the latch 122-124, supplies the 'force for pry-out action during the initial movement of the blades and thereafter supplies the force moving `the blades 3.L-31 around their pivot 32 to the fully opened position of Figure 3.

This desirable operation is achieved with a latch pry-out mechanism which `is relatively simple in construction, has a small number of parts and can be manufactured and assembled at a .relatively low cost and furthermore, does not require the extension of the blades 30-31 beyond the jaw break 40.

ln the foregoing, l have described my invention only in connection with preferred embodiments thereof. Many variations and modifications of the principles of my invention within the scope of `the description herein are obvious. Accordingly, i prefer to be bound not by the specific disclosure herein but only by the appending claims.

I claim:

l. In a disconnect switch having blades movable from an engaged to a disengaged position, said switch having a jaw end and a hinged end; said blades pivotally mounted on said hinged end; a Iresilient latch being rigidly mounted on the surface of said jaw end facing said hinged end; a pull ring pivotally mounted between said blades, a latch pin secured to said blades, said latch engaging said latch pin when said blades are in said engaged position; said pull ring effective to disengage said `latch from said latch pin upon rotation about its pivot.

2. In a disconnect switch having blades movable from an engaged to a disengaged position, said switch having a jaw end and Va hinged end; said blades pivotally mounted `on said hinged end; a resilient latch mounted on the surface of said jaw end facing said hinged end; a pull ring pivotally mounted between said blades, a latch pin secured to said blades, said latch engaging said latch pin when said blades are in said engaged position; said latch having ya cam surface; said pull ring having means to engage .said rcam surface to disengage said latch.

3. In a disconnect switch having blades movable from an engaged to a disengaged position, said switch having a jaw end and a hinged end; said blades pivotally mounted on said hingedjend; a resilient latch mounted on the surface of said jaw end facing said hinged end; a pull ring pivotally mounted between said blades, a latch pin secured ,to said blades, said latch engaging said latch pin when said blades are in said ,engaged position; said latch having a cam surface; `said pull ring having means to e11- gage said cam `surface to disengage said latch; said means engaging said jaw end of said switch after disengaging said latch, engagement of said means and said jaw end effective to provide pry out action for said disconnect switch.

4. Ina disconnect switch having blades movable from an engaged to a disengaged position, said switch having a j aw end `and a hinged end; said blades pivotally mounted on :said hinged end; a resilient latch being mounted on the surface of said 'jaw end facing said hinged end; a pull ring pivotally mounted between said blades, a latch pin secured' to said blades, said latch engaging said latch pin when said blades are insaid engaged position; said latch having a cam surface; said pull ring having means to engage said lcan; Surface to disengage said latch; said means engaging said jaw end of said switch after disengaging said latch, engagement of said means and said jaw end effective to provide pry out action for said disconnect switch; said means engaging said latch pin following the disengagement of said switch blade from said jaw end.

5. A latch and pry out mechanism for a disconnect switch; said latch being a resilient member having a hook and a cam surface; said resilient latch being rigidly mounted on the jaw end of a disconnect switch between the jaw end and hinged end thereof; a latch pin mounted on and between switch blades of said disconnect switch for engagement with the hook of said latch; said pry out mechanism being rotatably mounted on said switch References Cited in the file of this patent UNITED STATES PATENTS 2,203,350 Froland June 4, 1940 2,224,380 Crabbs et al Dec. 10, 1940 2,413,200 Thompson Dec. 24, 1946 2,498,250 Cole Feb. 2l, 1950 

